I think there is a much simpler explanation: childbearing is an extra effort for the organism, having the highest success rate with individuals in peak physical shape, so in order to maximize the number of food gatherers for the group, it makes sense to prevent older individuals from being exposed to the risk at all, and shutting down the whole mechanism further reduces their energy requirements.

The process only makes sense in species where individuals can live and contribute to a group long enough after the childbearing risk has reached some threshold. Also meaning, the longer and “more expensive” the pregnancy, the earlier that threshold might be reached.

Otherwise, if they don’t live in a group, and/or their average lifespan is not long enough, and/or the pregnancy is relatively short and inexpensive, the evolutionarily beneficial process is to keep trying to reproduce until the effort is too much and the individual dies, stopping to compete for resources.